This study aimed to investigate the roles of intracoronary derived coronary flow velocity reserve (CFVR) and myocardial perfusion scintigraphy (single photon emission computed tomography, or SPECT) for management of an intermediate lesion in patients with multivessel coronary artery disease.
Background
Evaluation of the functional significance of intermediate coronary narrowings (40% to 70% diameter stenosis) is important for clinical decision making and risk stratification.
Methods
In a prospective, multicenter study, SPECT was performed in 191 patients with stable angina and multivessel disease and scheduled for angioplasty (percutaneous transluminal coronary angioplasty, or PTCA) of a severe coronary narrowing. Coronary flow velocity reserve was determined selectively distal to an intermediate lesion in another artery using a Doppler guidewire. Percutaneous transluminal coronary angioplasty of the intermediate lesion was deferred when SPECT was negative or CFVR ≥2.0. Patients were followed for one year to document major cardiac events (death, infarction, revascularization), related to the intermediate lesion.
Results
Reversible perfusion defects were documented in the area of the intermediate lesion in 30 (16%) patients; CFVR was positive in 46 (24%) patients. Percutaneous transluminal coronary angioplasty of the intermediate lesion was deferred in 182 patients. During follow-up, 19 events occurred (3 myocardial infarctions, 16 revascularizations). Coronary flow velocity reserve was a more accurate predictor of cardiac events than was SPECT; relative risk: CFVR 3.9 (1.7 to 9.1), p < 0.05; SPECT 0.5 (0.1 to 3.2), p = NS. Multivariate analysis revealed CFVR as the only significant predictor for cardiac events.
Conclusions
Deferral of PTCA of intermediate lesions in multivessel disease is safe when CFVR ≥2.0 (event rate 6%). This selective evaluation of coronary lesion severity during cardiac catheterization allows a more accurate risk stratification than does SPECT, which is important for clinical decision making in this patient cohort.
Abbreviations
CFVR
coronary flow velocity reserve
ILIAS
Intermediate Lesions: Intracoronary Flow Assessment Versus 99mTc-MIBI SPECT study
Supported by the Dutch Health Insurance Board (grant 96-036) and by grant of the Netherlands Heart Foundation (grant 2000.090). R. A. Tio receives support from a grant (D95.019) of the Netherlands Heart Foundation. J. J. Piek is clinical investigator for the Netherlands Heart Foundation (grant D96.020).